using ICSharpCode.TextEditor.Document;

namespace ICSharpCode.TextEditor.Actions
{
    public class WordBackspace : AbstractEditAction
    {
        public override void Execute(TextArea textArea)
        {
            if (textArea.SelectionManager.HasSomethingSelected)
            {
                Delete.DeleteSelection(textArea);
                return;
            }
            textArea.BeginUpdate();
            LineSegment lineSegmentForOffset = textArea.Document.GetLineSegmentForOffset(textArea.Caret.Offset);
            checked
            {
                if (textArea.Caret.Offset > lineSegmentForOffset.Offset)
                {
                    int num = TextUtilities.FindPrevWordStart(textArea.Document, textArea.Caret.Offset);
                    if (num < textArea.Caret.Offset && !textArea.IsReadOnly(num, textArea.Caret.Offset - num))
                    {
                        textArea.Document.Remove(num, textArea.Caret.Offset - num);
                        textArea.Caret.Position = textArea.Document.OffsetToPosition(num);
                    }
                }
                if (textArea.Caret.Offset == lineSegmentForOffset.Offset)
                {
                    int lineNumberForOffset = textArea.Document.GetLineNumberForOffset(textArea.Caret.Offset);
                    if (lineNumberForOffset > 0)
                    {
                        LineSegment lineSegment = textArea.Document.GetLineSegment(lineNumberForOffset - 1);
                        int num2 = lineSegment.Offset + lineSegment.Length;
                        int length = textArea.Caret.Offset - num2;
                        if (!textArea.IsReadOnly(num2, length))
                        {
                            textArea.Document.Remove(num2, length);
                            textArea.Caret.Position = textArea.Document.OffsetToPosition(num2);
                        }
                    }
                }
                textArea.SetDesiredColumn();
                textArea.EndUpdate();
                textArea.Document.RequestUpdate(new TextAreaUpdate(TextAreaUpdateType.PositionToEnd, new TextLocation(0, textArea.Document.GetLineNumberForOffset(textArea.Caret.Offset))));
                textArea.Document.CommitUpdate();
            }
        }
    }
}
